1. Field of the Invention
The current invention relates to a high-pressure piston pump for a fuel system of an internal combustion engine, with a housing, at least one piston that defines a working chamber, a drive shaft that is supported in the housing by at least one shaft bearing and has at least one crank section, and a piston bearing that supports the piston at least indirectly against the crank section of the drive shaft, wherein at least one of the bearings between parts that move in relation to one another is a hydrostatic bearing, which is connected to the working chamber by means of a fluid connection.
2. Description of the Prior Art
A pump piston of the type with which this invention is concerned, in the form of a radial piston pump, is known from DE 197 05 205 A1. In this radial piston pump, a bearing race is placed onto the eccentric section of a drive shaft. This bearing race has a flat contact surface against which a sliding block of an axially reciprocating piston rests. Between the contact surface of the bearing race and the sliding block, there is a relief chamber, which communicates with a working chamber defined by the piston via axial bores in the sliding block and in the piston. When the piston executes a delivery stroke, the pressure in the working chamber increases, which is conveyed through the bore in the piston to the relief chamber and thus leads to a reduction in the contact force between the sliding block and bearing race. The relief chamber thus constitutes a hydrostatic bearing. This reduces the friction and wear between the sliding block and bearing race.
Although the efficiency of the known piston pump during operation has in fact proven to be favorable, it is nevertheless not yet optimal.
The object of the current invention, therefore, is to modify a piston pump of the known type so that it has an even better efficiency.
This object is attained in a piston pump of the type mentioned above by virtue of the fact that the fluid connection between the working chamber and hydrostatic bearing is provided with a device that can intermittently interrupt the fluid connection.